These locking track nuts will prevent the easy removal of your wheels from your frame. Wheel theft is extremely common and hex head track nuts are too easy to remove. These nuts can be used to secure fixed gear, single-speed and internally geared hubs. An ordinary wrench can not grab onto the specially shaped nut and bolt heads. Only the included wrench can engage the heads. Check to see the correct axle diameter on your bike before ordering. They come in M9 and M10 bolts.